Ten people are reported dead and more than 100 injured in the collision of two commuter trains north of Los Angeles early Wednesday.
Authorities in the town of Glendale say a southbound train hit a vehicle parked on the tracks, causing it to derail and strike another train coming in the opposite direction.
Glendale police chief Randy Adams said the vehicle was placed on the tracks deliberately by a man he described as suicidal.
He said the suspect, 26-year-old Juan Manuel Alvarez, left the vehicle before the train struck. The man is now in police custody and will be charged with homicide.
Rescue workers have spent the day pulling people from the wreckage of derailed and overturned train cars.
The U.S. National Transportation Safety Board is sending a team to join the investigation.
Some information for this report provided by AP.